Environmental Engineering Reference
In-Depth Information
Table 4
Diterpenes from marine sponge
Acanthella carvernosa
and their antifouling ac-
tivity [18-20]
Antifouling activity IC
50
(
µ
gmL
-1
)
Compound
Kalihinene X
3419
0.49
Kalihinene Y
3420
0.45
Kalihinene Z
3421
1.1
Kalihipyrans A
3422
1.3
Kalihipyrans B
3423
0.85
Kalihinol A
3414
0.087
10-Formamidokalihinene
3415
0.095
15-Formamidokalihinene
3424
0.14
Bifora-4,9,15-triene
3425
4.6
10-Formamido-5-isocyanatokalihinol-A
3426
ca. 0.05
10-Formamido-5-isothiocyanatokalihinol-A
3427
ca. 0.05
Cu
2
SO
4
0.15
tacorals
Renilla reniformis
and
Leptogorgia virgulata
, are potent inhibitors
of barnacle settlement, however, these are comparatively complex and
thus are not amenable to commercial exploitation. Clare et al. [22] ex-
amined about 20 analogues, bases on the functional groups of lactone
and furan rings in the parent molecules, such as 2-furyl-
n
-pentyl ketone,
khellin and
-decanolactone for anti-settlement activity and toxicity. Es-
pecially, 2-furyl-
n
-pentyl ketone
3417
(EC
set50
0.002
γ
µ
M) was more active
than copper (CuSO
4
·
5H
2
O) in preventing the settlement of diatom,
Nitzschia
spp. [22].
Fusetani et al. [18] isolated two new diterpene formamides along with
seven known ditepenes from a marine sponge
Acanthella cavernosa
at
Yakushima Island in Japan. These nine diterpenes showed potent antifoul-
ing activities against larvae of the barnacle
Balanus amphitrite
as shown in
Table 4 [19, 20]. The new kalihipyrans A (
3422
)andB(
3423
)inhibitedthelar-
val settlement and metamorphosis of the barnacle
Balanus amphitrite
with
IC
50
of 1.3 and 0.85
gmL
-1
, respectively. These activities are comparable to
those of kaihinene X-Z (IC
50
:
3419
= 0.49,
3420
= 0.45,
3421
= 1.1
µ
gmL
-1
),
whereas the corresponding isocyano compounds are more active (IC
50
:
3414
= 0.087,
3415
= 0.095,
3424
= 0.14
µ
gmL
-1
) [18]. Further, 10
µ
β
-formamido-5-
isocyanatokalihinol-A
3426
and 10
-formamido-5-isothiocyanatokalihinol-
A
3427
were highly antifouling with the IC
50
of only ca. 0.05
β
gmL
-1
[20]. It
µ
should be noted that these 10
-formamido-5-kalihinens
3426
and
3427
were
more active than CuSO
4
(IC
50
: 0.15
β
gmL
-1
), and their toxicities were quite
µ
low [24].